March 15, 2010— -- A tiny clip that holds together "floppy" halves of a leaky heart valve appears to be safer than surgical repair and has comparable efficacy at one year, heart researchers say.
At 30 days less than 10 percent of the patients treated with the clip had complications such as the need for blood transfusions versus 57 percent of the patients who had surgery, said Dr. Tom Feldman of Northshore University Health System in Evanston, Ill., who led a study called EVEREST II in which 136 patients were treated with the device, while 80 patients had surgical repairs. He reported the results at the American College of Cardiology meeting in Atlanta, Ga.
At 12 months, 72 percent of the patients treated with the device, called MitraClip, were still symptom-free or had only minor symptoms. That was good enough to be judged comparable to the surgery patients, even though the surgery results look better at one year with 90 percent of those patients still had a good clinical outcome.
The leaky valve condition, called mitral regurgitation, is diagnosed in about 250,000 Americans every year. When the valve fails to close properly it causes blood to flow backward, which decreases the efficiency of the heart. Patients with severe regurgitation develop irregular heartbeats and heart failure.
Treatment for the condition includes medical therapy, which is used in patients who have only mild symptoms. But in patients with severe symptoms -- meaning they cannot perform normal functions such as walking short distances without experiencing pain or breathlessness, surgical repair of the leaky valve or surgery to replace the valve with a mechanical valve is the gold standard treatment.
The device tested by Feldman is a tiny clip that acts like a clothes pin to hold together the valve flaps.
The clip is mounted on a catheter and then threaded up into the heart through an incision in an artery in the groin.
Unlike surgery patients who have a painful recovery from the open heart procedure, the patients treated with clip are up and walking quickly. "They feel better and don't have the pain that surgery patients experience," Feldman said in an interview with MedPage Today.
But 12 months may not be enough time to make an assessment of clinical efficacy, said Dr. Alfred Bove of Temple University in Philadelphia. "A mechanical valve will last 35 years, but you need to have the patient on Coumadin, but a surgical repair will last 15 years and you don't need [a blood thinner]."
In that context, "12 months is peanuts," said Bove, who is ACC president. He was not involved in the study.
The study recruited 279 patients and randomized 184 to an endovascular repair procedure and 95 to surgery. Out of the endovascular treatment patients, the procedure was attempted in 178 patients and successful in 136.
Bove found the more than 40 failed attempts at repair with the clip to be concerning. "That's a high rate, and that's in a trial that used the best [doctors]." He predicted that the failure rate is likely to be somewhat higher if less experienced interventionalists attempt the procedure.
Dr. Timothy Gardner, a heart surgeon and medical director at Care Center for Heart and Vascular Health in Wilmington, Del., said the study's design raised red flags for him.
For example, Gardner said that adverse events following "any surgery" are most common during the first 30 days, whereas "one expects a low 30-day [adverse event] rate" with a catherter-based treatment.
Moreover, he found the stroke and death rates to be "on the high side." Asked about the transfusion rate, Gardner said it was difficult to determine "what that means," but he said that at least some of the transfused units probably reflect blood needed to "prime the pump" for patients on the bypass machine. Surgical patients would be on bypass, the device patients would not.
Feldman said the transfusions did indicate an adverse event and he pointed out that "transfusion is, itself, a risk factor for poor outcome."
Gardner, who is a former president of the American Heart Association, also questioned the 12 month efficacy measure. "I'm a little concerned that it looks like almost 30 percent of the device patients have failed the procedure by 12 months," he said.
If the U.S. Food and Drug Administration approves the device, the task of credentialing physicians to use it will initially fall to the company, Bove said. "Eventually, we'll have some requirements incorporated into guidelines, but all of that is down the road," he said.